Space telegraphy.



O. O. RODS.

SPACE TELEGRAPHY. APPLIdATION FILED JUNE 10,1907.

901,649. Patented'Oct. 20, 1908.

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O. G. RODS.

SPACE TELEGRAPHY.

APPLICATION FILED JUNE 10, 1907.

' Patented Oct. 20, 1908.

8 SHEETS-SHEET 2.

SPACE TELEGRAPHY.

APPLICATION FILED JUNE 10, 1901.

1 901,649. I Patented Oct. 20, 1908.

8 SHEETS-SHBET 3.

0. 0. RODS.

SPACE TELEGRAPHY.

APPLICATION FILED JUNE 10, 1907.

901,649, Patented Oct. 20, 1908.

8 SHEETS-SHEET 4.

WITHEEE E SPACE TELEGRAPHY. AYPLIOATION FILED mm 10, 1907.

901,649. Patented Oct. 20, 1908.

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SPAGE TELEGBAPHY. APPLICATION FILED Jun 10, 1907.

Patnted Oct. 20, 1908.

\X/ITHEEEEE SPAOE TELEGBAPHY.

APPLICATION FILED JUNE 10,. 1901.

Patented 00c. 20, 1908.

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901,649. I Patented 0c't.20,1908.

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I To all it may concern:

UNITED s'rATEs PATENT OFFICE. i

OSCAR 0. R008, OF NEWTON, MASSACHUSETTS, ASSIGNOR TO STONE TELEGRAPH AND TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

SPACE TELEGRAPHY.

Be it known that I, OsoAR 0. Boos, a ci'ti-' .ze'n of. the United States, and a resident of Newton, in thecounty of Middles'ex and State of Massachusetts, have invented a new and useful Im rovement in Space Telegraphy, of which t e following is a specification.

' tion.

My invention relates to apparatus for simultaneously transmitting and receiving The object of my-invent1on is to provide a duplex space telegraph system in which the apparatus are transmitting and receivingl 't the'antenna or permanently connected W1 elevated conductor and are constructed and arranged to be operated simultaneously without mutual interference.

My invention may best be understood by having reference to the drawings which accompany and form a part of this specification and which'represent in diagram several arrangements of apparatus and circuits embodying the rinciples of said invention; but

I it will be un erstood that I do not limitmyself to the particular systems therein shown, inasmuch as the'latter are subject to a wide range of variation without departing from said principles.

In the drawings Fi ures 1 1* and 2 are diagrams hereinafter re erred to for the purpose of explaining certain features of m inven- Figs. 3, fl and 5 represent dup exwire less telegra h systems. Figs. '6, 7, 8' and 9 show modi cations of the systems illustrated in Fi%. 3, 4 and 5.

*igs. 3 to 9 inclusive,O is a symbol employed torepresent capacity andL is a sym- 1 ol employed to represent inductance. The

variouscapacities and iuductancesshown in said figures are differentiated by the use of subscripts and exponents while in Figs. 6 to 9, inclusive, they are further differentiated by the use of refixes.

In each of the systems hereinafter described; the essential features are an elevated conductor connected in series with a parallelbranch circuit containing capacity and inductance in each of its branches, a resonant receiving circuit associated with both branches of said parallel-branch circuit, and an oscil lation producing circuit associated with said elevated conductor. An earth connector constructed to have practically zero react once for the fundamental frequency of the elevated conductor may be connected in se- Speciflcation of Letters Patent.

. Application filed June 10, 1907. Serial No. 878,098.

' Patented 0a: 20, 1908.

' ries with the latter and in parallel withthe parallel-branch circuit.

My "nvention resides in. the proportionment of the electromagnetic constants of the several elements above referred to whereby the transmitting and receiving apparatus may be simultaneously employed Without mutual interference.

Referring. toFigs. 1, 1 and 2, it has been demonstrated that the variation with frequency for persistent electrical oscillations of the reactance of a arallel-branch circuit of the type shownin ig. 1 having an induct: I

ance L and a condenser O in one branch and an inductance L" and a condenser O in the other branch, follows the lawgraphically represented in Fi 1. As shown. in, Fig. 1,

which is acurve, rawh to rectangular coordinates, theordinates representing reactance and the abscissae representing, frequency, the

reactance of the parallel-branch circuitis zero for two frequencies A and A, is ne atlve between zero and Aand between Z and A and Fig. 2 is a curve the abscissae as in Fig. l'j representing frequency and the ordinates representing cur rent am litude. Fig. Zrepresents the varia tion wit frequency of the current develo ed in a circuit of the type shown in Fig. 1 a w en acted u on by presistent electrical forces,

quency designated at Z, the. ordinate of the current-frequency curve is ractically zero.

and that on either side of the curves are somewhat similar in shape. will be obvious that the constants of the two branchesof. the parallel-branch circuit may be so chosen that currents equal: in ampli- It wil be noted that for a particular fre Accordingly it tude and in phase, or equal in amplitude and i opposite in phase, may be developed in sald Y branches by an electromotive forceofwpredetermined frequency. *1

Referring to Fig. 1, C'a L a represents an elevated conductor, l a being the secondary of an oscillation'transformer the primary of which may form a producing circuit 0 the type commonly emrtion of an oscillation- 1 10 loyed in space telegraphy. The parallel- C'b and U6 Cb. The resonant receiving circuit which may be associated in any of the usual ways with both branches of said parallel-branch circuit is designated by L'c'Cc. The earth connector which is connected in series with the elevated conductor and in parallel with the parallel-branch circuit is shown at L d Od.

It will. be noted that the parallel-branch circuit above referred to is of the type shown in Fig. 1 and that the variation with frequency of the reactance thereof and the current therein may be graphically represented by curves of the type shown in Figs. 1 and 2. For more complete explanation of the derivation of said curves reference may be made to the patent to Stone 884,109, dated April 7, 1908, in Fig. 4 of which the curve (6) corresponds to the curve shown in Fig. 1 of this application.

he function of the earth connector Ld Cd had been fully set forth in the patent to Stone 884,107, dated April 7, 1908, and briefly stated is as follows: The earth connector is attuned to the fundamental frequency of the elevated conductor, that is to say, each, when isolated, has zero reactance for the oscillations of the lowest frequency natural to the elevated conductor, and therefore for oscillations of said frequency the reactance of the system consisting of said elevated conductor and earth connector is zero. This being the case the reaction of the arallel branch circuit on the elevated con uctor system consisting of said elevated conductor in series with said earth connector is practically zero for oscillations having a frequency equal to the fundamental of said elevated conductor. If therefore the oscillations developed by the oscillation-producing circuit or transmitting apparatus be equal in frequency to that natural to the elevatedconductor, a practically infinite impedance will be opposed to such oscillations by the parallel-branch circuit, while the impedance of the earth connector for such "oscillations will be practically zero.

While I prefer to employ the earth connector in each of the systems herein described, it will nevertheless be obvious that the same may be dispensed with, especially when the frequency to which the resonant receiving circuit is attuned is widely different from that of the oscillations developed by the oscillation-producing apparatus.

When the frequency of the currents devel- 0 ed in the elevated conductor system by t e oscillation-producing circuit which is associated therewith is such that the reactance of both branches of the parallel-branch circuit is negative or that of both branches is positive, a resonant receiving circuit such as shown in Fig. 4 maybe employed and the windings. of both the secondaries which associate said resonant receiving circuit with the parallel-branch circuit may be the same in sense, and when said frequency is such that the reactance of one branch of said parallelbranch circuit is positive and that of the other is negative, the windings 'of said secondaries may be opposite in sense, as ii1dicated in Fig. 3.

- The following table is added herewith, not for the purpose of limiting my invention to the values therein set forth, but for the purpose of disclosing several specific arrangements of circuits which have been found in practice to be eflfective. In this table, station 1 and station 2 have reference to the stations shown in Figs. 3, 4 and'5, each station being a complete transmitting and receiving station, and the sole difference between the figures being that in Fig. 1 the secondaries in the resonant receiving circuits are differentially connected (this of course being equivalent to the direct connection of two secondaries oppositely wound), in Fig. 4 the said secondaries are both wound in the same direction and are directly connected, and in Fig. 5 the secondaries of the resonant receiving circuit at station 1 are directly connected and those at station 2 are differentially connected. and nr employed in said table indicate the frequencies to which various elements of the system are attuned, as follows: nt, the transmitting frequency, is that to which the elevated conductor system consisting of the ele-' vated conductor Oa La' and the earth connector U01 U01 is attuned and consequently is the frequency of the oscillations produced by the oscillation circuit inductively associated with the coil L a. 11/17 is the frequency to which the branch circuit Lb U?) is attuned and W7) is the frequency to which the branch L?)' 0'6 is attuned. nr, the receiving frequency, is thatto which the resonant receiving circuit U0 U0 is attuned. In like manner the symbols nt nb 'n,b and nr re resent the frequencies'to which the several elements of station 2 are attuned, nt beingthat of the elevated conductor and earth connector, nb that of the branch Lb Cb, nb that of the branch L b Cb, and 'nf'r that of the resonant receiving circuit L"c Cc. The numerals in the columns headed by the bove mentioned symbols represent the v ave lengths in meters corresponding to the frequencies in question. Thus 800'in column nt and line A indicates that the elevated conductor system in sta-.

tion 1 is attuned to a frequency which corresponds to a wave length of 800 meters. Case A gives the constants for circuits arranged as shown in Fig. 3, case B those for circuits arranged as shown inFig. 4, and cases 0 and D those for circuits arran ed as shown in Fig. 5. It willbe noted in eac case that the transmitting frequency of station 1 is equal to the receiving frequency 'of station 2, and converselyz- Station 1. Station 2. Case.

I r Gu ub u l 11 A.. 800 .760 840 300, 300 280 320 800 ,B-.... 300 760 840 800 1 500 250 320 300 C 300 760 840 800 800 760, 840 300 D 800 760 840 300 I 300 760 840 800 hen the several circuits are roportioned in accordance with the above, table, or in numer'ous other ways that will readily occur to those skilled in the art, the currents devel oped in the elevated conductor system b T the oscillation producing circuit associated t erewith will produce no effect in the home reso-.

nant receiving circuit due to the fact that the currentsin the two branches of the parallelbranch circuit are exceedingly minute because 'of the ractically infinite impedance of said aralle brarrch circuit for currents of the.- equency produced by the oscillation producing circuit and due to the further fact that such currents as are develo ed in said parallel branch-circuit are neutr'a ized in the resonant receiving circuit in the manner above set forth.

n will be readilyapparent. that the earth connector need not be employed, especially when 'the resonant receiving circuit is attuned to a frequency which is widely dif- 'ferent from that of the oscillations developed by the home oscillation producing. circuit;

' but when said earth connector is employed it affords further security to the resonant're .ceiving circuit, because it provides a path to earth of practically zero impedance in shunt to the parallel-branch circuit when the elevated conductor system is energized by the oscillation producing circuit.

The oscillations developed in the elevated conductor system at stationl produce elec-.

tromagnetic waves of the frequency to which the resonant receiving circuit of station 2 is attuned and it will be found, if the constants of the foregoing table are employed, that the entire system at station 2 consisting of the elevated conductor,parallelsbranch circuit and earth connector, has for said frequency a pronounced rate of vibration, that usual ways.

for said frequency the earth connector of station 2 has a high impedance and that the currents in the parallel-branch circuit of said station are not equal in amplitude. The oscillations therefore which are developed in the system at station 2 by waves radiated from the s stem at station 1, create currents of relative y large amplitude in the resonant receiving circuit of station 2 and operate the oscillation detector-which may be associated with said circuit in any of the lonversely the oscillations impressed upon the elevated conductor system of station 2 by its oscillation producing cir- I tions of a frequency corresponding to one of p the pronounced rates of vibration of said system and to which the resonant receiving circuit of station 1 is attuned. For a more complete explanation of the facts above enumerated attention is called to the patentto Stone No. 884,107, April7, 1908, especially Fig. 7 thereof, and the patent to Stone No. 884,109, April 7, thereof. v I

In the modificationillustrated in Fig. 6 I have shown meansior obtaining additional protection for the home resonant receiving circuit, consisting in .theinterposition between said resonant receiving circuit and the parallel-branch circuit 1/1) (1'?) LbCb of a second circuit consisting of the coil 1908, especially Fig. "5 Y 1 SL'a and the condenser SOa connected in I series. with a second parallel-branch circuit having in one branch the coil SIN) and the condenser SCb and in the other branch-the coil SL b and the condenser SCb. In this case the resonant circuit U0 U0 is attuned to the frequency of the waves radiated from the distant transmittin station and the above .mentioned second ranged that one of its most pronounced rates of vibration is e ual to that of the frequency to which sai resonant circuit is attuned, sucharrangement having been fully described in the patent to Stone No. 884,106, April 7, 1908. The resonant re ceiving circuit SLc SCc' is attuned to the frequency of the waves developed at the distant transmitting station. A second earth connector SL-(d SCd, attuned to the same frequency as the earth connector. Ld Cd and the elevated conductor Ca La, may be employed to connect one side of the second circuit to earth anda conductor my may connect the other side of said second circuit to :earth.

Fig. 7' shows a further modification in which I make use of the principle set forth in the patentto Stone 884,106, April 7, 1908',

circuit is so 'arl'lO and the patent to Cram 884,076, April 7,

1908, that a parallel-branch circuit contain ing capacity in one'br'anch and inductance in the other. is the equivalent of a capacity or of an inductance according to the fre uenc'y of theforces acting on the circuit. 4

n the present instance, comparing Fig. 7 with Fig. 5, it will be seen that I sorted in one branch of the parallel-branch circuit a second parallel-branch circuit IL IC IL ICand in the other branch an other parallel-branch circuit IL IC'IL LC. In the system shown in Fig. 7, as in that shown in Fig. -5,the oscillations impressed on the system by the-home oscillahave in tion producing circuit are neutralized with PL and IL are pair by pair opposite in cillatiori-producing circuit and the system phase, the resonant receiving circuit L 0 (3'0 may be associated with all of said coils in the mannershown in Fig. 8. In this case the amplitude of the currents developed in the resonant receiving circuit by an electrometive force ofthe frequency to which said circuit is attuned will be greater other things being equal than in the case illustrated in Fig. 7 because for forces of the frequency to which said circuit is attuned the currents in said coils are not opposite in phase.

Inasmuch as a parallel-branch circuit having capacity in one branch and inductance in the ot er may be made to have a capacity reactance or an inductance reactance depending upon the frequency employed, as more fully explained in the patent to Stone 884,106, April 7, 1908, above referred to, in connection with Fig. 6 thereof, I may eliminate the serially connected coils and condensers Lb L b (3'1) 0'1) of Fig. 8 and thereby arrive at the system of circuits shown in Fig. 9, in which the operation is the same as that above set forth in connection with Fig.8. One of the chief advantages of the system herein described is that thereby a receiving operator may cut in upon the transmission from a distant station when he fails to understand a portion of a message. This he does merely by depressing his transmitting key and signaling Bk. (break) whereupon the distant transmitting operator who sends with his head telephone in position and who receives by such telephone the break signal between his own signal ele-- ments ceases to send and receives from the other operator instructions for repeating that portion of the original message which was not understood.

I claim:

1. In a space telegraph system, an elevated conductor, a parallel-branch circuit connected in series therewith and containing capacity and inductance in each of its branches,'a-resonant receiving circuit associated with both branches of said parallelbranch circuit and an oscillation-producing circuit associated with said elevated conduo-tor, the said resonant receiving circuit having}; very high impedance for oscillations of the frequency generated by said oscomprising said elevated conductor and parallel-branch circuit having a very low impedance for oscillations of the frequency to which said resonant receiving circuit is attuned. r

, 2. In a space telegraph system,- an elevated conductor, a parallel-branch circuit connected in series therewith and containing capacity and inductance in each of its branches, a resonant receiving circuit associated with both branches of said parallelbranch circuit, an oscillation-producing circuit associated with said elevated conductor, the said resonant receiving circuit having a very high impedance for oscillations of the frequency generated by said oscillation-producing circuit and the system com rising said elevated conductor and parallelranch circuit having a very low impedance for oscillations of the frequency to which said resonant receiving circuit is attuned; and an earth connector in series with said elevated conductor and in-parallel with said parallelbranch circuit, said earth connector having practically zero impedance for the funda- 7 ductor, said parallel-branch circuit having a very high impedance for oscillations of the frequency generated by said oscillation-producing circuit and the system comprising said elevated conductor and parallel-branch circuit having a, very low impedance for oscillations of the frequency to which said resonant receiving circuit is attuned.

4-. In a space telegraph system, an elevated conductor, a parallelbranch circuit connected in series therewith and containing capacity and inductance in each of its branches, a resonant receiving circuit associated with both branches of said parallelbranch circuit, an oscillation-producing circuit associated with said elevated conductor, said parallel-branch circuit having a very high impedance for oscillations of the frequency generated by said oscillation-producing circuit and the system comprising said elevated conductor and parallel-branch circuit having a very low impedance for oscillations of the frequency to which said resonant receiving circuit is attuned;- and an earth connector in series with said elevated conductor and inparallel with said parallelbranch circuit, said earth connector having practically zero impedance for the fundamental frequency of said elevated conductor.

In testimony whereof, I have hereunto subscribed my name this 7th day of June OSCAR 0. R008. Witnesses CHARLES C. KURTZ, Gno. K. Woonwonrn. 

